Monday Sourdough Sandwich Bread

Monday Sourdough Sandwich Bread
Square bread loaf tin
https://www.pantrymama.com/sourdough-sandwich-bread-super-simple-sandwich-bread-with-a-soft-crust/
Two sets of measurements, one for 1 loaf and another for 2 loaves. Made in a stand mixer.

===2 loaves:===
1000 g Bread Flour
200 g Sourdough Starter fed and bubbly
560 g Water
120 g Butter Cubed
30 g Salt
===1 loaf:===
500 g Bread Flour
100 g Sourdough Starter fed and bubbly
280 g Water
60 g Butter Cubed
15 g Salt

MIX starter, flour, and water to make a shaggy dough in stand mixer. (30 seconds)
AUTOLYSE 30 minutes
ADD butter, salt. Mix for 1 minute.
REST I - 30 minutes
KNEAD I - 3 minutes (butter should be well incorporated at this point)
REST II - 30 minutes
KNEAD II - 2-3 minutes, dough should start slapping the sides of the bowl
BULK FERMENT cover in plastic wrap, leave in oven at proof setting til just under doubled in size (NOTE: takes about 4 hours for me)
PREPARE TIN butter it
SHAPE then plop into tin
FINAL RISE in oven on proof setting til it passes the finger poke test (indentation very slowly fills in) (NOTE: takes about 6-8 hours)
PREHEAT 350 deg F
BAKE 40+ minutes til top is golden brown
COOL at least 90 minutes